diff --git a/kernel/events/core.c b/kernel/events/core.c index e0c193083aa0568bba58b6ee6198225dc8257d3b..7b185e630e08cadaae3b5045f3e3b1a6a4a57950 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6477,6 +6477,10 @@ perf_sample_ustack_size(u16 stack_size, u16 header_size, if (!regs) return 0; + /* No mm, no stack, no dump. */ + if (!current->mm) + return 0; + /* * Check if we fit in with the requested stack size into the: * - TASK_SIZE @@ -7065,6 +7069,9 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs) const u32 max_stack = event->attr.sample_max_stack; struct perf_callchain_entry *callchain; + if (!current->mm) + user = false; + if (!kernel && !user) return &__empty_callchain; diff --git a/kernel/exit.c b/kernel/exit.c index 26a81ea631567eba6adea87713a4c262e8a63918..63d2a54a5d97c603406eb5f25237135b4bfe95aa 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -802,6 +802,14 @@ void __noreturn do_exit(long code) */ if (group_dead) sp_group_exit(); + /* + * Since sampling can touch ->mm, make sure to stop everything before we + * tear it down. + * + * Also flushes inherited counters to the parent - before the parent + * gets woken up by child-exit notifications. + */ + perf_event_exit_task(tsk); exit_mm(); @@ -819,14 +827,6 @@ void __noreturn do_exit(long code) exit_task_work(tsk); exit_thread(tsk); - /* - * Flush inherited counters to the parent - before the parent - * gets woken up by child-exit notifications. - * - * because of cgroup mode, must be called before cgroup_exit() - */ - perf_event_exit_task(tsk); - sched_autogroup_exit_task(tsk); cgroup_exit(tsk);